The first and most important rule to recover files is to not use the system in a write mode.
So best to only boot from a live medium and to mount the partition that contains the files in read only.
Then since you have a fresh install, I assume you have btrfs. In that case the following tutorial might help: https://forum.manjaro.org/t/how-to-rescue-data-from-a-damaged-btrfs-volume/79414
Disclaimer: I have not read nor tried that tutorial myself.
Edit: fixed link